Reciprocating internal combustion engine with constant pressure combustion

ABSTRACT

A reciprocating internal combustion engine adapted to provide substantially constant pressure combustion in a combustion chamber separated from the compression and expansion cylinders of the engine is provided.

United States Patent 708,236 9/1902 Leonard Glenn 8. Warren 1361 Myron St., Schenectady, N.Y. 12309 806,159

Mar. 11, 1969 May 4, 1.971

lnventor Appl. No. Filed Patented RECIPROCA'IING INTERNAL COMBUSTION ENGINE WITH CONSTANT PRESSURE COMBUSTION 11 Claims, 8 Drawing Figs.

US. 60/39.63, 60/3969, 123/ 188GC Int. F02g 3/02 Field of Search 123/188 972,504 10/1910 Brown 60/39.63X 1,876,160 9/1932 Zahodiakin 123/188(GL) 2,140,085 12/ 1 938 Maina 60/ 39.63X 2,396,347 3/ 1946 Sanders 123/ 1 88(GCL) 2,425,630 8/ 1947 McCollum 158/ 1R.L.UX 2,603,949 7/ 1952 Brown 60/3965 2,977,759 4/1961 Milliken 60/39.63 3,030,773 4/1962 Johnson 60/ 39.69X 3,099,910 8/1963 Schinner 60/ 39.65X 3,338,051 8/ 1967 Chamberlain et a1 60/3965 FOREIGN PATENTS 294,797 8/ 1928 Great Britain 60/3963 826,402 1/ 1960 Great Britain 60/3965 Primary Examiner-Allan D. Herrmann Attorney-Kane, Dalsimer, Kane, Sullivan and Kurucz ABSTRACT: A reciprocating internal combustion engine adapted to provide substantially constant pressure combustion in a combustion chamber separated from the compression and expansion cylinders of the engine is provided.

PATENTEDHAY 4m: 3571729 sum 2 8F 4 N NTOR 440v .nameg/v ATTORNEYf ZA WM RECIPROCATING INTERNAL COMBUSTION ENGINE WITH CONSTANT PRESSURE COMBUSTION BACKGROUND OF THE INVENTION In recent years, automotive engineers have become increasingly aware of the problems of smog production and air pollution resulting from the large concentrations of noxious materials in internal combustion engines and particularly automobile exhaust fumes. Research into the smog making potential of present automobile exhaust indicates that muchof the difficulty and particularly the concentration of unburned hydrocarbon present in exhausts is the result of flame quenching of the combustible mixture of air and fuel during combustion. This flame quenching occurs in the upper end of the engine cylinder and on the piston head as a result of the combustible material contacting the relatively cold cylinder and combustion chamber walls. In addition, a heavy concentration of the unburned hydrocarbon content and carbon monoxide of the exhaust issues during idling, deceleration, and following cold starts as a result of the engine mixture being very rich in fuel to ensure smooth and powerful operatron.

Further, large amounts of carbon monoxide, unburned hydrocarbon and nitrogen oxide are exhausted during the frequent heavy acceleration periods when combustion temperatures are high and the combustible mixtures are made very rich to promote top level performance.

Further air pollutants in the form of lead compounds result from the various additives present in common automotive fuels which are designed to increase the octane rating of the fuels. High nitrogen oxide concentrations exist in diesel-type engine exhausts.

Although some progress has been made in minimizing and reducing automotive air pollution, the above-stated causes of air pollution are inherent in most reciprocating internal combustion engines available today. These engines are characterized by having the compression combustion and expansion strokes of their power cycle occurring in the same chamber and they operate under constant volume combustion conditions (i.e., the Otto cycle) or try to operate at nearly constant pressure combustion (i.e., the diesel cycle) but in a combustion chamber integral with the expansion cylinder.

Experience with aircraft and other gas turbine engines, with steam boilers and turbine engine gas heaters in which combustion takes place in a separate chamber at nearly constant pressure, with excess air and at a relatively slow rate as compared to the explosive diesel engine has shown that the exhaust of such combustion can be extremely low in carbon monoxide, unburned hydrocarbons, and nitrogen oxides. Also, the absence of an explosive combustion eliminates the need for detonation suppressors such as lead additives in the fuel.

The present invention has as its primary objective to adapt a modified version of the Brayton cycle of thermodynamics utilizing constant pressure combustion to a reciprocating internal combustion engine and to thereby obviate all the abovementioned causes of air pollution and at the same time provide an engine, the efficiency of which is higher than that of presently available automotive power plants. Such high efficiency is possible because of the high compression ratio and high temperatures permitted by providing the combustion chamber with cooled walls.

SUMMARY OF THE INVENTION In accordance with the present invention, a reciprocating internal combustion engine adapted to provide substantially constant pressure combustion is provided with at least one each of suitably interconnected compression cylinders, combustion chambers, and expansion cylinders. Thus, each engine includes at least one air compression cylinder having a piston shiftably mounted therein and containing suitable inlet and outlet valves. The outlet valve controls the fiow of compressed air from the compression cylinder to a combustion chamber while preventing backflow from the combustion chamber back to the compression cylinder. The combustion chamber is defined within an elongated enclosure having air and fuel inlet ports and ignition elements disposed at one end thereof. Conduit means connect the other end of the combustion chamber to the head of an expansion cylinder containing a timed inlet valve and also containing a shiftably mounted piston. The compression cylinder piston and expansion cylinder piston are connected to a common crankshaft so that their respective motions are synchronized and maintained in the proper cyclical phase relationship.

Means are associated with the combustion chamber to confine the heat generated during combustion combustion to the longitudinal center of the chamber. The aforementioned means include a stainless steel liner disposed about the inner face of the combustion chamber designed to rereflect radiant heat back to the center of the combustion chamber; means for providing helical swirl 'to the air from the compression cylinder as it enters the combustion chamber; means for providing a relatively high velocity combustion-free airflow along the interior wall of the combustion chamber; and means for inducing a backflow in the secondary and tertiary air supply provided for the" combustion chamber. The engine is also provided with improved outlet valve means for the compression cylinder and improved inlet valve means for the power cylinder which are particularly designed to operate at low-pressure loss at high speed. The power cylinder inlet valve is further designed to operate at high temperature.

BRIEF DESCRIPTION OF THE DRAWINGS I pression cylinder outlet valve of the present engine;

FIG. 3 is a fragmentary, side elevational sectional view taken along reference lines 3 3 of FIG. 2;

FIG. 4 is a fragmentary, enlarged, side elevational sectional view of the expansion cylinder head;

FIG. 5 is a fragmentary side elevational sectional view taken along reference lines 5-5 of FIG. 1 depicting the combustion chamber of the present invention;

FIG. 6 is a fragmentary top plan view of a bank of compression cylinders for an engine incorporating the present invention;

FIG. 7 is a top plan view similar to FIG. 6 of the expansion cylinder bank of an engine incorporating the present invention; and

FIG. 8 is an enlarged fragmentary sectional view of the power cylinder inlet valve.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The present invention is illustrated in the accompanying FIGS. wherein similar components are indicated by the same reference numeral throughout the several views. Reference is now made to FIG. 1 in particular wherein the engine 10 of the present invention is depicted. As shown, the engine, in cross section, closely resembles the V-type of automotive engine presently available and in fact may be based upon the conventional V-8 engine or be of the V, configuration where n is any even number. The engine 10 may also be built as an in-line engine of any even number of cylinders where half the cylinders are used for compression and the other half are used for power. However, it is felt that the advantages inherent in the present V-type engine configuration will also apply to the improved engine of the present invention and hence this description of the preferred embodiment will be confined to a V-type engine.

The engine 10 comprises two banks of angularly disposed cylinders including in this example a left bank of cylinders which comprise the compression cylinders 12 and a right bank of cylinders 13 which contain the power cylinders 14. A single combustion chamber 16 extends between the right and left banks of cylinders and is connected thereto by suitable manifolds.

COMPRESSION CYLINDER Each compression cylinder 12 comprises a hollow, elongated member disposed at a suitable angle relative to the engine block 18 and having a closed head 20 at one end thereof. Two inlet valves 22 are provided in the cylinder head along with a single multiple unit outlet valve 24. Two inlet valves are provided because there is space to accommodate both valves and this arrangement will improve the volumetric efficiency of the engine at higher speeds.

Inlet valves 22 are operated by cam 26 through follower 28 and lifter 30. Cam 26 in turn is shown in this embodiment as driven by the timing gear belt 32 shown in phantom which drives the overhead camshaft 33 at one-half the crankshaft speed. The operation of the valves is in accordance with standard automotive principles and is well known in the art. Cooling in the form of a water jacket 34 is provided about the cylinder walls and portions of the cylinder head and serves to reduce the power required for compression and to permit good lubrication. As with presently available engines, the water jacket may be cast integral with the engine block and cylinder head. An air inlet manifold 36 is provided which communicates with the interior of cylinder 12 through passageways controlled by each of the two inlet valves 22. An air filter (not shown) may be provided at the inlet end of the manifold to remove impurities from the air supply to the com pressor.

A piston 38 is shiftably disposed within the barrel of cylinder 12 in a manner such as that presently employed in automotive engine design. In this regard, one end of piston 38 terminates in a head 40 that is provided with suitable piston rings 42 to sealingly engage the inner surface of the cylinder barrel. The lower end of connecting rod 39 is coupled to a crankshaft 44. Crankshaft 44 is common to all the cylinders in both the compression and power banks of the engine.

The highly compressed air exhaust of compression cylinder 12 is adapted to flow past valve 24 through conduit 46 to the combustion chamber 16 when valve 24 is suitably opened by air pressure under it. At other times, namely, when the compression cylinder is actively compressing a quantity of air, or sucking in a new charge of air on the suction stroke, valve 24 is closed thereby preventing passage of the air to the compression chamber. Valve 24 thus serves as an outlet valve for compression cylinder 12 and an inlet valve for the combustion chamber 16.

Reference is now made to FIGS. 2 and 3 wherein a fragmentary section of valve 24 is shown in enlarged form. As shown, valve 24 actually comprises a cluster of several small valves, in this case seven valves arranged in a group with six valves 48 set at approximately 60 angles with respect to each other about a center valve 50. The construction of the center subvalve 50 and the peripheral valves 48 are identical. The aforementioned arrangement may also be seen in FIG. 2 and FIG. 6. The cluster of valves is contained beneath a removable porous cage 52 which allows the passage of compressed air therethrough so that when valve 24 is open, air will flow from the compression cylinder to the combustion chamber. Each subvalve (48 and 50) comprises a substantially flat stainless steel disc 54 seated in the enlarged midsection 56 of bore 58 that extends through the head 20 of cylinder 12 into the interior of the cylinder barrel. Shoulders 61 define the upper terminal of the lower portion 63 of the passageway of bore 58 that communicates with the cylinder barrel. The valves (48 and 50) are self-acting, nonreturn valves that are biased in the closed position against shoulder 61 by springs 60, as shown in solid line in FIG. 3. Thus, when the discs 54 assume the solid line position depicted in FIG. 3, the various passageways between the compression cylinder interior and combustion chamber 16 are effectively blocked, thereby preventing passage of compressed air from the cylinder 12 to the combustion chamber. However, when pressure builds up within compression cylinder 12 during the upward stroke of piston 38, the force on the underside of each disc 54 will increase sufficiently to overcome the biasing force of spring 60 and the disc 54 will be forced upwardly away from shoulders 61, thereby opening valve 24 and providing a path, through passageway 64, to conduit 46. Shoulder 62, spaced upwardly from shoulder 61, is provided to limit the displacement of disc 54 when valve 24 is forced open. The path of compressed air from the compression cylinder 12 through valve 24 toward conduit 46 is shown by the arrows on FIG. 3. It should be obvious that passageway 64 must communicate with the annular spacing defined between shoulders 61 and 62 which limit the displacement of disc 54. It should also be obvious that the top side of cage 52 must communicate with conduit 46 which extends between the compression cylinder and the combustion chamber 16.

The reason for making the compressor outlet valve 24 in the form of a cluster of smaller subvalve members rather than a single large valve is that inherently the smaller subvalves, due to the relatively low weight of their moving elements, can operate with lower pressure drops and lower metal stresses than could larger valves, and thus could operate at higher speeds than could larger valves. This is especially important in view of the high speeds required by modern automotive engines which are in the range of 4,000 rpm.

COMBUSTION CHAMBER Combustion in the proposed engine of the present invention takes place in combustion chamber 16. Combustion chamber 16 includes an elongated body member 63 having an inlet end terminal portion proximal the compressor cylinder bank 12 and an outlet end proximal the power cylinder bank 13. In the design of the engine including the timing of the opening and closing of the engine inlet valves, it will be possible to provide that in operation combustion gasses are leaving the combustion chamber at the same rate as compressed air and fuel are introduced into the combustion chamber so that the pressure within the chamber will remain substantially constant except for slight ripples as the valves open and close and thus provide relatively constant pressure combustion. The level of this pressure at any particular engine speed depends upon the amount of fuel injected relative to the airflow. Thus, at high load and high fuel flow, the pressure will be relatively high. The power output of the engine will depend upon the fuel fed The inlet end terminal portion of combustion chamber 16, as shown in FIG. 5, consists of an outer, nearly hemispherical cap 66 containing a fuel spray nozzle 68 as well as air nozzles 70 and 72. An inner liner 69 is spaced apart from the interior walls of the inlet end of the combustion chamber. Nozzles 70 and 72 communicate with the outlet of conduit 46 while the fuel nozzle 68 forms the outlet of a fuel pump that is not shown. It should be noted that air nozzles 70 and 72 are offset somewhat from one another and thus serve to provide rotational motion or swirl to the incoming air supply. This rotational motion cooperates in containing the combustion reaction away from the surfaces of the liner by forming a helical vortex of the gasses within the chamber. In this regard, centrifugal force will force the cold, relatively dense unreacted air toward the walls of the chamber and the hot relatively light gasses of the combustion reaction will be displaced toward the center of the chamber. A spark plug or glow point 74 is also provided in the inlet end of the combustion chamber 66 extending through liner 69 and serves to ignite the fuel and air mixture shortly after they enter the combustion chamber. Since combustion within chamber 16 is constant, the octane and cetane specification of the fuel used does not afiect the performance of the engine and hence lower cost and cleaner burning fuels than gasoline may be used, although any grade of commercial gasoline could be burned with no difficulty.

As was previously discussed, one of the principal causes of automotive engine exhaust air pollution results from flame quenching" of the fuel-air mixture during combustion. This is caused by the combustible gasses contacting the relatively cold surfaces of the combustion chamber while combustion is occuring. Under these conditions, the flame is quenched when it reaches a layer of such combustible gasses from 3 to 5 thousandths (0.003 to 0.005) of an inch thick near the wall. The incomplete combustion resulting leaves unburned hydrocarbons in the mixture which go out of the exhaust to contribute to smog making material in the atmosphere. The present invention obviates this cause of air pollution by providing means for containing the combustion reaction substantially to the longitudinal center of the combustion chamber 16 and away from the walls of the chamber. It further permits combustion always with an excess of air. To this end, a stainless steel liner 76 is provided disposed about and in contact with the inner surface of the combustion chamber wall. Liner 76 serves to rereflect radiant heat energy back toward the longitudinal center of the combustion chamber 16 while combustion is occuring and to reduce the heat loss to the cooled walls of the combustion chamber;

If the engine is to be operated in supercharged condition or if it is designed to operate only at loads which can be obtained with a substantial amount of excess air, the combustion chamber may be air cooled instead of water cooled. In this regard, the liner 76 will be spaced somewhat from the combustion chamber wall and air is directed between the liner and wall to provide the necessary cooling in place of the water jacket. The liner may also be provided with inwardly directed louvers and perforations which serve to provide additional rotational motion to the incoming gasses. The perforations serve to introduce secondary and tertiary air into the combustion reaction downstream of cap 66.

In any event, the cap liner 69 is spaced apart from the interior of cap 66 and this spacing defines a passageway 81 through which some of the air from nozzle 70 and 72 flows. A circumferential opening 80 is provided between the liner 69 and the walls of the combustion chamber and serves to allow secondary air from the passageway 81 to reach the flame downstream of the inlet end of combustion chamber 16. This permits the combustion at the entrance end of the combustion chamber that is fuel rich but ensures the engine s running on an overall air-rich mixture at all times, thus removing another of the causes of air pollution previously discussed. Suitable deflection vanes can be put in this annular opening 80 to increase the helical swirl of the secondary air coming out of the opening, if required.

The openings 80 also sefve to provide a supply of air along the inner surface of the liner thereby removing any carbon deposits that might otherwise tend to form. The dimension of openings 80 are maintained very much less than the flow area of the combustion chamber thus causing the longitudinal velocity of the air flowing from openings 80 along the inner surface of the liner to be substantially greater than the velocity of the primary air and combustion products going down the centerline of the combustion chamber. The difference in velocity between the primary air and combustion gasses and the air from the openings 80 causes a turbulence to occur which is shown by the arrows in FIG. 1. This backflow provides still additional or tertiary air to the combustion reaction for more complete combustion of the fuel and also cooperates in directing the combustion reaction toward the longitudinal center of chamber" 16 and away from the chamber walls. Thus, the combustion reaction receives primary air from nozzles 70 and 72, secondary air directly from passageway 81 through opening 80 and tertiary air which is the backflow of air through opening 80. A water jacket 82 is provided about the combustion chamber and serves to cooperate in cooling the combustion chamber walls. This water jacket may be integral with the water jacket 34 cooling the heads of the power cylinders 14 and will thus eliminate the use of bolted joints which could present problems at the high pressures and temperatures contemplated. The combustion chamber 16 has at its downstream end individual short passages and 92 which extend between the combustion chamber 16 and the entrance to the inlet valve 96 to the expansion cylinders 14 which serves as the power unit.

POWER CYLINDER The construction of each of the power cylinders 14 is very similar to that of the compression cylinders 12 and to that of present engines and to this end comprise hollow, elongated members disposed in this case at an angle relative to that of the compression cylinders. A piston 88 is shiftably disposed within the barrel of cylinder 14 and one end of the piston connecting rod 89 is coupled to crankshaft 44. Thus, the motion of piston 88 of the power cylinder is synchronous to the motion of piston 38 of the compression cylinder although the two are out of phase with each other. The head 84 of piston 88 is provided with suitable rings to seal the cylinder barrel and piston.

The hot gasses of combustion developed in the combustion chamber 16 are used to drive piston 88 downwardly during the engine power stroke. In this regard, the gasses flow through manifold passages 90 and 92 which extend between the downstream end of the combustion chamber 16 and the valve controlled openings 94 in the expansion cylinder head. Inlet valves 96 and 96a seated in openings 94 and 94a respectively are operated by cam 98 through follower 100 and lifter 102. The overhead camshaft 104 is driven from the crankshaft by timing gear belt 106 which is synchronous with the compression cylinder timing gear belt 32 in a manner similar to that employed on presently available V-8 automobile engines. An exhaust valve 107 is also provided which controls the flow of gasses from the power cylinder to the exhaust manifold 108 after the power stroke is completed. This valve is also cam operated. In this case, due to the fact that this expansion cylinder has a power stroke every revolution, this camshaft should be driven at crankshaft speed in order to get a good cam configuration geometrically.

Because of the high heat generated in the combustion chamber and consequently the high temperature to which inlet valves 96 and 96a are subjected to, it may be necessary to provide means for cooling this valve in order to permit the engine to efficiently operate at high speeds. In this regard, reference is made to FIG. 8 wherein it is shown that some of the high-pressure uncombusted air from the compressor discharge and before the combustion chamber will be piped to entrance 112 on FIGS. 1 and 8 whereby this high-pressure air enters the annular chamber at the top of the valve stem bushing for valve 96. There is therefore a flow of such air downwards toward the head of valve 96 and into the volume ahead of it so as to preclude hot combustion gases going up along the valve stem. This air exerts a cooling action on valve 96 and tends to push the hot combustion gases away from the valve and stem when the valve is closed. Some of this cooler high pressure air will also go upward through the valve stem bushing clearance into the cylinder under the piston shown on top of valve stem 110. The high-pressure air also cooperates by means of the cylinder and piston shown on the upper end of the inlet valve stem which is slightly larger in diameter than the inlet valve itself with the spring 1 14 in keeping the valve in a closed position during the appropriate portions of the engine cycle, thus permitting the use of a less stiff spring and ensuring that the inlet valve will be tight against leakage when closed.

This arrangement automatically increases the closing force on this valve as the pressure in the combustion chamber rises during high loads and reduces the closing force and hence the cam opening force at all times that the engine is operating at reduced loads.

As was previously mentioned, the valve is cam operated and in this connection, it is designed to open at top dead center and close quickly thereafter at some portion of the piston stroke called the cutoff point. The extent of the cutoff point determines the pressure level of the engine operation. In this connection, the optimum point for cutoff has been found to be within 12 percent and 20 percent of the stroke or at 40 to 55 after top dead center.

Further cooling of the valve head may also be attained by following out the valve stem and providing a small quantity of sodium within the bore so produced. This is a process well known and widely used in the reciprocating engine industry.

Thus, in accordance with the present invention, a new and improved reciprocating automotive engine is provided which is adapted to operate in a thermodynamic cycle with relatively constant pressure combustion and in a combustion chamber separate from the cylinders.

I claim:

1. ln a heat engine of the type including an air compressor, a reciprocable air compressor member within said air compressor, a hot gas engine, a reciprocable hot gas engine member within said hot gas engine, crankshaft means of said heat engine mechanically connecting said reciprocable members, a constant pressure combustion chamber interconnecting the high-pressure end of said air compressor with the high-pressure end of said hot gas engine, and combustion within said combustion chamber being achieved at full load at substantially the stoichiometric cycle temperature, that improvement consisting of a liquid coolable head portion of said hot gas engine, a path for combustion products formed in said head portion whereby the high-temperature high-pressure products of combustion can be introduced from said combustion chamber into said hot gas engine, said head portion extending from said combustion path and the high-pressure end of said hot gas engine to a location of said combustion chamber remote from the high-temperature high-pressure products of combustion, a liquid coolable jacket portion of said combustion chamber extending from said head portion and integral therewith along the high-temperature end of the combustion chamber, sealing means between said head portion and said jacket at a location remote from the hot gases and the remainder of said combustion chamber, and said sealing means being of the relatively low-temperature type as a result of being located remotely from the high-temperature products of combustion.

2. A heat engine in accordance with claim 1 in which said hot gas engine is provided with multiple cylinders and each having a liquid coolable head portion integral with each other and with said liquid coolable jacket portion of said combustion chamber and inlet valve means are provided in the respective combustion product paths of said head portions.

3. The invention in accordance with claim 2 wherein each of said inlet valve means includes a valve stem and means are provided for directing a supply of air from said air compressor to said inlet valve stem wherein said air supply serves to cooperate in cooling said inlet valve means by directing the hot gases of combustion away from the valve during those portions of the engine cycle when said valve is closed.

4. A heat engine in accordance with claim 1 in which means are provided associated with said combustion chamber to confine the heat generated during combustion to the longitudinal center of said combustion chamber to minimize heat loss to the surfaces of said combustion chamber and prevent quenching and the production of pollutants.

5. A heat engine in accordance with claim 4 in which a plurality of passages are provided between the high-pressure end of said air compressor and said combustion chamber, a low inertia member within each of said passages, spring means yieldingly urging each of said low inertia members into a blocking position in its respective passage, and stop means for each respective low inertia member whereby upon pressure buildup in said air compressor the force of each of said springs will be overcome and each of said low inertia members will be moved against its respective stop means allowing compressed air to move in said passages from said air compressor to said combustion chamber and upon subsequent reduction of ressure in said air compressor said low inertia members W] 1 be moved by said spring means to said blocking position.

6. In a heat engine of the type including an air compressor, a reciprocable air compressor member within said air compressor, a hot gas engine, a reciprocable hot gas engine member within said hot gas engine, crankshaft means of said heat engine mechanically connecting said reciprocable members, a constant pressure combustion chamber interconnecting the high-pressure end of said air compressor with the high-pressure end of said gas engine, and combustion within said combustion chamber being achieved at full load at substantially the stoichiometric cycle temperature, that improvement consisting of connecting the high-pressure end of said air compressor and said combustion chamber with secondary nozzle means for imparting a motion to primary air introduced into said combustion chamber, and thus imparting a helical, rotational motion to said primary air and the combustion reactants within said chamber whereby to create a hot center in said chamber due to centrifugal force directing the hot, less dense combustion products toward the center of the chamber and the colder, more dense, unreacted combustion mixture away from the chamber center thereby confining the heat generated during combustion to the longitudinal center of said combustion chamber to minimize heat loss to the surface of said combustion chamber and prevent quenching and the production of pollutants.

7. A heat engine in accordance with claim 6 in which a liner is provided disposed about and in contact with the inner surface of the combustion chamber wall providing an interface which impedes transfer of heat between the inner portion of said combustion chamber and the surface of said combustion chamber.

8. A heat engine in accordance with claim 7 in which a reflecting surface is provided on said liner whereby radiant heat energy is reflected back toward the longitudinal center of the combustion chamber.

9. The invention in accordance with claim 7 wherein said combustion chamber is provided with an inlet end terminal portion of generally semihemispherical configuration; said combustion chamber further includes a second liner disposed within and spaced apart from said inlet end terminal portion whereby to define a passageway terminating in an annular opening between said inlet end and said second liner; means for connecting said passageway with the outlet of said air compressor whereby secondary air is adapted to be directed into the combustion chamber downstream of said inlet end terminal portion through said passageway opening.

10. The invention in accordance with claim 9 wherein the flow area of said combustion chamber greatly exceeds the flow area of said passageway opening so as to provide a relatively high longitudinal velocity to the tertiary air along the inner surface of said combustion chamber which flows through said opening whereby to cooperate in holding and stabilizing the combustion reaction within the chamber at substantially the longitudinal center of said chamber and away from said inner surface.

11. The invention in accordance with claim 10 further comprising deflection vanes disposed within said passageway openings, said deflection vanes being adapted to provide helical motion to said tertiary air supply and thereby cooperate in maintaining said combustion reaction away from said chamber walls. 

1. In a heat engine of the type including an air compressor, a reciprocable air compressor member within said air compressor, a hot gas engine, a reciprocable hot gas engine member within said hot gas engine, crankshaft means of said heat engine mechanically connecting said reciprocable members, a constant pressure combustion chamber interconnecting the high-pressure end of said air compressor with the high-pressure end of said hot gas engine, and combustion within said combustion chamber being achieved at full load at substantially the stoichiometric cycle temperature, that improvement consisting of a liquid coolable head portion of said hot gas engine, a path for combustion products formed in said head portion whereby the high-temperature high-pressure products of combustion can be introduced from said combustion chamber into said hot gas engine, said head portion extending from said combustion path and the high-pressure end of said hot gas engine to a location of said combustion chamber remote from the high-temperature high-pressure products of combustion, a liquid coolable jacket portion of said combustion chamber extending from said head portion and integral therewith along the high-temperature end of the combustion chamber, sealing means between said head portion and said jacket at a location remote from the hot gases and the remainder of said combustion chamber, and said sealing means being of the relatively low-temperature type as a result of being located remotely from the hightemperature products of combustion.
 2. A heat engine in accordance with claim 1 in which said hot gas engine is provided with multiple cylinders and each having a liquid coolable head portion integral with each other and with said liquid coolable jacket portion of said combustion chamber and inlet valve means are provided in the respective combustion product paths of said head portions.
 3. The invention in accordance with claim 2 wherein each of said inlet valve means includes a valve stem and means are provided for directing a supply of air from said air compressor to said inlet valve stem wherein said air supply serves to cooperate in cooling said inlet valve means by directing the hot gases of combustion away from the valve during those portions of the engine cycle when said valve is closed.
 4. A heat engine in accordance with claim 1 in which means are provided associated with said combustion chamber to confine the heat generated during combustion to the longitudinal center of said combustion chamber to minimize heat loss to the surfaces of said combustion chamber and prevent quenching and the production of pollutants.
 5. A heat engine in accordance with claim 4 in which a plurality of passages are provided between the high-pressure end of said air compressor and said combustion chamber, a low inertia member within each of said passages, spring means yieldingly urging each of said low inertia members into a blocking position in its respective passage, and stop means for each respective low inertia member whereby upon pressure buildup in said air compressor the force of each of said springs will be overcome and each of said low inertia members will be moved against its respective stop means allowing compressed air to move in said passages from said air compressor to said combustion chamber and upon subsequent reduction of pressure in said air compressor said low inertia members will be moved by said spring means to said blocking position.
 6. In a heat engine of the type including an air compressor, a reciprocable air compressor member within said air compressor, a hot gas engine, a reciprocable hot gas engine member within said hot gas engine, crankshaft means of said heat engine mechanically connecting said reciprocable members, a constant pressure combustion chamber interconnecting the high-pressure end of said air compressor with the high-pressure end of said gas engine, and combustion within said combustion chamber being achieved at full load at substantially the stoichiometric cycle temperature, that improvement consisting of connecting the high-pressure end of said air compressor and said combustion chamber with secondary nozzle means for imparting a motion to primary air introduced into said combustion chamber, and thus imparting a helical, rotational motion to said primary air and the combustion reactants within said chamber whereby to create a hot center in said chamber due to centrifugal force directing the hot, less dense combustion products toward the center of the chamber and the colder, more dense, unreacted combustion mixture away from the chamber center thereby confining the heat generated during combustion to the longitudinal center of said combustion chamber to minimize heat loss to the surface of said combustion chamber and prevent quenching and the production of pollutants.
 7. A heat engine in accordance with claim 6 in which a liner is provided disposed about and in contact with the inner surface of the combustion chamber wall providing an interface which impedes transfer of heat between the inner portion of said combustion chamber and the surface of said combustion chamber.
 8. A heat engine in accordance with claim 7 in which a reflecting surface is provided on said liner whereby radiant heat energy is reflected back toward the longitudinal center of the combustion chamber.
 9. The invention in accordance with claim 7 wherein said combustion chamber is provided with an inlet end terminal portion of generally semihemispherical configuration; said combustion chamber further inCludes a second liner disposed within and spaced apart from said inlet end terminal portion whereby to define a passageway terminating in an annular opening between said inlet end and said second liner; means for connecting said passageway with the outlet of said air compressor whereby secondary air is adapted to be directed into the combustion chamber downstream of said inlet end terminal portion through said passageway opening.
 10. The invention in accordance with claim 9 wherein the flow area of said combustion chamber greatly exceeds the flow area of said passageway opening so as to provide a relatively high longitudinal velocity to the tertiary air along the inner surface of said combustion chamber which flows through said opening whereby to cooperate in holding and stabilizing the combustion reaction within the chamber at substantially the longitudinal center of said chamber and away from said inner surface.
 11. The invention in accordance with claim 10 further comprising deflection vanes disposed within said passageway openings, said deflection vanes being adapted to provide helical motion to said tertiary air supply and thereby cooperate in maintaining said combustion reaction away from said chamber walls. 